Sponsored Content
Top Forums UNIX for Dummies Questions & Answers What does this command do? and how to decode all other lines Post 302965095 by Aia on Saturday 23rd of January 2016 03:57:08 PM
Old 01-23-2016
Quote:
Code:
eval "$(dd if=$0 bs=1 skip=69 2>/dev/null|gpg -d 2>/dev/null)"; exit

dd reads from if=$0 one block size of 1 at a time bs=1 starting at the 70th block (skipping 69 characters). $0 is the script name of itself from where this command is issued. It outputs to stdout. The block skipped at the begging is the eval statement.

Take a look at how many characters long that line is, including the newline that it would be in the file.
Code:
echo 'eval "$(dd if=$0 bs=1 skip=69 2>/dev/null|gpg -d 2>/dev/null)"; exit' | wc -c

Code:
69

2>/dev/null is there to not pollute the stdout with the content that is piped to gpg:
gpg -d with the -d flag is to decrypt. In this case, it is not doing it from a filename but from stdin piped from the stdout of dd.
Again, 2>/dev/null will prevent pollution from any warning or status update that it will produce, essentially, disregarding those.
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Please decode in English

Hello: Can anyone please decode this script in English. I have also made some comments which I know.. The actual script does not have one comment also.. #! /bin/ksh . odbmsprd_env.ksh #setting the env.. echo $0 Started at : `date '+%d-%m-%Y %H:%M:%S'` # what's echo $0 ... (4 Replies)
Discussion started by: ST2000
4 Replies

2. Programming

gunzip and base64 decode a string

I am writing a C program to get messages from a JMS queue into a string variable and then write them to a database. The messages are compressed (gzip) and encoded (base64), so I need to be able to perform gunzip and base64 decode inside the C. I don't want to write any of the messages to file so... (2 Replies)
Discussion started by: handak9
2 Replies

3. Shell Programming and Scripting

Decode email

In pine email, when you receive an email with an attachment, the content of the attachment is incoded (content-transfer-encoding: base64). I am trying to write a shell script that will read the mail file, and it will save the attachment of an email to a directory. I want to do this by reading... (6 Replies)
Discussion started by: mskarica
6 Replies

4. Shell Programming and Scripting

auto decode a value to different value

Okay, This is not something I've tried to do before, but what I want (need) to do is when a value is read in it gets changed to the value needed. I've been given a list of ids that I need to check against the ids I have in my system, but as is the case we don't have the same naming convention... (2 Replies)
Discussion started by: nhatch
2 Replies

5. Programming

Help to decode in perl script

Hi, I am having a file in below stucture: header { subheader1 { field1 : value field2 : value field3: value } //end of subheader1 subheader2 { subheader3 { field4 : value field5 : value field6: value } subheader4 (6 Replies)
Discussion started by: kallol
6 Replies

6. Programming

How to Decode an image using openGL

Hi, How to decode an image using openGL library libjpeg .. which are the steps needed to do this using C language.. actually my work is to decode the image, store it on the buffer, and place it on cube surface.. please guide me,,any answer will appreciated .. (8 Replies)
Discussion started by: Ravikishore
8 Replies

7. Linux

Decode the statement!!

What will the below statement do ?:confused: && { && {eval `/bin/setup 1`} || && { VAR="/tmp" } export $VAR; } (3 Replies)
Discussion started by: krishnaux
3 Replies

8. AIX

How to decompile or decode an executable?

I have a file type of: executable (RISC System/6000 V3.1) or obj module not stripped How can I decode it? I know that this may be somewhat involved, but if you could steer me in the right direction, I would appreciate it. Thanks! (2 Replies)
Discussion started by: gg48gg
2 Replies

9. Shell Programming and Scripting

How to decode text files?

HI experts....I am trying to decode some text files... I need little help from you people...file is of mixed type...from generated from windows based system my text files looks like this... 2.AUBZ 158 1 11 116204310 6 N 7542 E 18 02846 52833 102821 152815 ... (9 Replies)
Discussion started by: Akshay Hegde
9 Replies

10. UNIX for Beginners Questions & Answers

Decode a file

hi i have this file : <?xml version="1.0" encoding="UTF-8"?> <OnDemand xmlns="http://xsd.telecomitalia.it/Schema/crmws.entity.OnDemand" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xsd.telecomitalia.it/Schema/crmws.entity.OnDemand... (2 Replies)
Discussion started by: Francesco_IT
2 Replies
bup-margin(1)						      General Commands Manual						     bup-margin(1)

NAME
bup-margin - figure out your deduplication safety margin SYNOPSIS
bup margin [options...] DESCRIPTION
bup margin iterates through all objects in your bup repository, calculating the largest number of prefix bits shared between any two entries. This number, n, identifies the longest subset of SHA-1 you could use and still encounter a collision between your object ids. For example, one system that was tested had a collection of 11 million objects (70 GB), and bup margin returned 45. That means a 46-bit hash would be sufficient to avoid all collisions among that set of objects; each object in that repository could be uniquely identified by its first 46 bits. The number of bits needed seems to increase by about 1 or 2 for every doubling of the number of objects. Since SHA-1 hashes have 160 bits, that leaves 115 bits of margin. Of course, because SHA-1 hashes are essentially random, it's theoretically possible to use many more bits with far fewer objects. If you're paranoid about the possibility of SHA-1 collisions, you can monitor your repository by running bup margin occasionally to see if you're getting dangerously close to 160 bits. OPTIONS
--predict Guess the offset into each index file where a particular object will appear, and report the maximum deviation of the correct answer from the guess. This is potentially useful for tuning an interpolation search algorithm. --ignore-midx don't use .midx files, use only .idx files. This is only really useful when used with --predict. EXAMPLE
$ bup margin Reading indexes: 100.00% (1612581/1612581), done. 40 40 matching prefix bits 1.94 bits per doubling 120 bits (61.86 doublings) remaining 4.19338e+18 times larger is possible Everyone on earth could have 625878182 data sets like yours, all in one repository, and we would expect 1 object collision. $ bup margin --predict PackIdxList: using 1 index. Reading indexes: 100.00% (1612581/1612581), done. 915 of 1612581 (0.057%) SEE ALSO
bup-midx(1), bup-save(1) BUP
Part of the bup(1) suite. AUTHORS
Avery Pennarun <apenwarr@gmail.com>. Bup unknown- bup-margin(1)
All times are GMT -4. The time now is 04:54 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy